Synthesizers are instruments that allow you to manipulate a wave form to create interesting and unique sounds. The sounds you create with a synth can illustrate many tones, some tones you may chose to create may be aggressive or emotional. Mick Gordon uses synthesizers a lot during his work on DOOM, these are mainly used to create aggressive tones to the music or lead the music as a synth lead. Learning how to effectively use synthesis can be tricky to understand at first, but understanding it is a very important skill in the musical composition and production industry.
What is a Wave form?
A wave form is the signal of the wave displayed on a graph to tell us it’s behaviour over time, for example this graph could display it’s increase and decrease in dynamics over time. Wave forms inside of synths oscillate (can move up, down and left to right). There are four basic forms of sound waves, these are: Sine waves, Square Waves, Saw-tooth waves and Triangle waves. There are more than the four types of waves I have mentioned, however those are the basic waves that are most commonly used in synthesise.
The Sine Wave
Sine waves are purest form of waves and their shape resembles that of the letter ‘S’, these waves are the most basic form of sound waves. Sine Waves are home to only one frequency, because only one frequency is present subtractive synths will not work on a sine wave. This is because subtractive synthesise must require the attendance of other frequencies to filter them out, the sine wave only has one frequency meaning there is nothing to subtract from the sound wave. However low passing a triangle wave can transform a triangle wave into a sinusoidal wave. Because of the lack of other frequencies the sine wave has no harmonics, this is because a harmonic is a secondary frequency unique to the fundamental wave, a sine wave only contains one frequency meaning there is no harmonics. A sine wave can make a very nice sub bass. this is because it only consists of one frequency so their is no need to filter the sub bass to get rid of harmonics.
The Triangle Wave
The triangle wave is similar to the sine wave, however it includes harmonic frequencies. These frequencies are made up of odd harmonics, odd (uneven) harmonics can also be seen in the square wave. The difference between the two waves is that the harmonics in a triangle wave roll off faster. The triangle wave generally works well as a sub-bass or bass because of how fast it’s harmonics fall off and how easily it can blend into music.
Square Wave
The square wave has more harmonics than the triangle wave, the sound of the wave is similar to the sounds you would hear it 8-bit video games. High harmonics in square waves tend to roll off slower than they do in triangle waves. Just like the triangle wave, square waves are made up of only odd harmonics. Square waves are unique to other typed of waves because we have control over it’s PMW (Pulse Width Modulation). This controls the width of the gaps between the waves, this gives us the ability to decrease and increase the space between the gaps, which alters the tone of the frequency. Generally square waves work well as synth leads, pads and bass sounds because of it’s rch harmonics and rough texture.
Saw-tooth waves
Saw-tooth waves are full of harmonics, because of this they are often described to have a rough and harsh tone to it. The overall sound of a saw-tooth wave is gritty and sounds like a buzz. This wave type is unique to the others I have mentioned because it is not just made up of uneven harmonics, but also even harmonics. Just like the square wave saw-tooth waves generally make good synth leads, pads and bass sounds because of their rough texture.
AMPLITUDE
Amplitude is what measures the height of a wave form, in terms of music this is the dynamics of the sound. Here are a couple examples of amplitude, a whisper would be displayed as having a low amplitude becuase of how quiet it is. A jet engine however has a large amplitude because of how loud it is.
Envelopes
Envelopes are tools that control the evolution of a sound from it’s beginning to it’s end. The most common type of envelope is a amp envelope, this controls the amplitude of a synth over time. Another type of envelope is a brightness envelope, this controls the brightness of a sound over time. Brightness is the amount of pitch, loudness and treble in a sound opposite to it’s bass
Frequency And Hertz
Frequency is how fast a waveform repeats every second, frequency is measured in ‘Hertz’. 1 hertz means that 1 the wave form is moving at 1 hertz per second, if a waveform is moving at 20 hertz it is moving at a frequency of 20 hertz per second. This would give off a very low pitch, this is because the lower the frequency, the lower the sound we will receive. If an oscillator is moving at 20,000 hertz per second the waveform would be a lot faster, therefore the frequency would be a lot higher. A good metaphor for increase in frequency is in a car engine. A car cruises at an average frequency of 2,000 to 3,000 RPM, this is equal to 20-30 hertz. This is around the lowest octaves the average human can hear. A faster car such as a F1 car has a much faster engine, which has a frequency of around 1200 hertz this is much higher than the average car. The meaning of this metaphor is that frequency is made up of how fast a waveform vibrates.
Frequency is what we measure the pitch in but Hertz (Hz) is what we use to measure the frequency of a sound. 1 Hz means that a sound will be oscillated 1 time every second. If you set an LFO’s rate to 4 Hz the LFO will be forced to repeat 4 times a second. Therefore Hz is how many times the synthesiser oscillates per second. Making the Hertz slowly increase can build up intensity in a piece of music, this technique is used often in dubstep beat drops.
Oscillators
An oscillator is the part of the synth that produces the sound, oscillators create an electronic signal that vibrates back and forth. How fast the wave oscillates determines the pitch of the frequency, this is the oscillator controls how fast the sound wave vibrates. Oscillators use specific voices to emit wave forms such as: sine, square, triangle and saw-tooth. Each of these wave forms have their own distinctive timbre. Some synthesisers only have one oscillator, but most have multiple oscillators that can all play at one time. Playing multiple oscillators at once can lead to layered and multi-timberal sounds
Filters
Filters are used to remove unwanted background noises from your sounds, it does this by filtering out the unwanted noises so that only the noises you want are in your final sound. Through a filter we can decide to get rid of specific frequencies we do not want, and even increase or decrease the frequencies volume. Oscillators tend to have bright tones to them which emit high frequencies. These higher frequencies can be removed with a low pass filter, a low pass filter removes or dulls the higher frequencies of the sound making the lower frequencies stand out. A high pass frequencies does the exact opposite of this and makes the higher frequencies more dominant.
Timbre
Timbre is the tone of the sound, it is the distinct characteristic in a sound that differentiates one sound from another. Timbre will be the reason you can tell the difference between multiple sounds despite the fact that they are playing the same note with the same amplitude. When describing timbre we often use words such as: brassy, round, bright sharp and reedy. There are different categories of timbre to help us distinguish it’s sound, one example of a timbre category is strings. The string family contains instruments such as: violins, cello and violas. These instruments each have similar timbres and tones, however each instrument has distinct traits. Even some violins sound different from each other, one might have different strings that give off a darker sound while the other generates a brighter sound. Violins can also be used to create different timbres by using it’s bow in different ways while playing it.
LFO
LFO stands for low frequency oscillator, an LFO emits electronic signals that give off a really low frequency compared to other oscillators. LFO’s are often so low they are beyond the range of human hearing which is around 20 HZ. Although LFO’s often can’t be heard they create a back and forth wave form movement similar to that of a pendulum. The pendulum movement pattern can be used to create a lot of different musical effects. The oscillation of the LFO does not colour the sound of the music, however it can be used to control parameters of the music. If the LFO’s pendulum swing is assigned to a volume knob it creates a tremolo which is a repeating change in amplitude. If the LFO is assigned to a frequency parameter it gives us vibrato, which is a repeating change of pitch patterns. Next if we assign the LFO to a cut-off frequency parameter of a filter it creates a cycling variation of timbre. This creates a wobbling bass sound, this effect is used in many bass line to create a wobbling effect.
Modulation
Modulation is another word for change, modulation is often referred to when a key changes in the middle of a song. A famous example of modulation is used in the song ‘Love On Top’ by Beyoncé. At the end of the song there is 4 key modulations that occur, each modulation raises the harmonics root of the song by half a step. This creates a harmonic ascending line, in this example modulation is referring to a changing the songs harmony or key centre.
Frequency Modulation
Frequency modulation is when you use one sound wave to modulate another wave. Frequency modulation has effect on the phase on the synth and can create really interesting sounds if it used correctly. Using frequency modulation on 2 waves with high harmonics such as the saw and square wave can create aggressive sounds in synthesise.
Attack
Attack controls how fast it will take for the note to reach it’s maximum volume level after the key is pressed. When you press a key on the piano you will instantly hear that note at it’s maximum volume, this means the attack speed for a piano is 0 milliseconds. On an envelope maximum volume is represented by the number 100, while the minimum is 0 which is silence.
Hold
Hold is a parameter that is not found in most synths, however it is still important to know how it works. Hold controls how long the sound of synthesiser will remain at maximum volume before proceeding to the decay stage of the sound.
Decay
Decay controls how long it takes for the sound of the envelope to decrease in volume after it has reached it’s dynamics peak of 100. With attack we control how fast we reach the maximum volume, decay controls how fast we reach the minimal volume.
Sustain
The sustain parameter decides at what point the decay phase ends, this means the decay will only drop to the point where the sustain is set. If the sustain is set to 100 it will cancel out the decay phase, this is because 100 is the full volume and the decay wont drop below any number we set. If the sustain is set 50 the decay will reach half the volume of the maximum sound.
Release
Release controls how long it will take for the sound of the envelope to fade out after a note has been released. If you let go of a note at the value of 100 the release will decrease in value from 100 to 0. This means maximum volume to silence, so the release will always decrease the value of the key you released to silence (0).
Effects And Distortion
Saturation and distortion
Saturation and distortion are the first effects I am going to talk about. Both saturation and distortion are similar in terms of what they do, they both increase the harmonics of the sound of the synth. However distortion is a much more intense version of saturation and can produce very aggressive tones. Saturation and distortion work very well on bass frequencies, they can make them sound extra gritty or warm sounding. Bit crusher is another type of distorti0on that crushes down the sound, this can be used to produce 8-bit sounds in the synth or can produce a lo-fi hip hop sound.
Phaser, Flanger and Chorus
Phaser and flanger are effects that can add more texture to your music. This is because the sounds duplicate the input of the sound and modulate the delay time. This means the track will be automatically layered and will be filled out with delay. Using these effects wisely can create very interesting and tense music. Out of the two flanger is a more intense and thick version of phaser. Another effect similar to phaser and flanger is chorus, this effect almost does the same job. Just like the 2 pervious effects it does duplicate the audio signal to add delay to it, but it also detunes the duplicated audio signal meaning the sound will be playing two different pitches at once.
Unison and Detune
On most synths there will be an effect called unison, this is will duplicate the sound and have it play different pitches in each duplicate. Unlike phaser, flanger and chorus the synth will add no delay to the unison, unison can create very powerful and intimidating sounds in your music. Detune is the pitch of the sound being produced and how it changes, if you gradually increase the unison and detune of a sound it sounds like the audio is widening. This because it will start to expand to fill out the frequency spectrum, this is what gives unison it’s large sound, in unison the same notes will be played but in different octaves. You alter how large you want your unison to be by adding more voices to the synth, if you use 3 voices the synth will be playing 3 notes in unison. You can experiment with detune to create a pulsating sound in the synth, this can be done by increasing the detune with the unison.
deadmou5’s pluck technique
The pluck technique is a synth technique made famous by the popular music producer deadmou5. Here is a step by step guide to making the deadmou5 pluck. First of all set both oscillators to saw waves, both oscillators must have 4 to 16 voices of unison and a bit of detune. This will create a powerful sound with high harmonics due to the saw waves. Next you will have to enable a low pass filter, this will get rid of all the rich and high harmonics and tones in the synth. The next step is to add an ADSR (attack, decay, sustain and release) envelope to the filter cut off, this will allow you to have more control over the synth. Set both the attack and sustain to 0. This will mean you sound will immediately reach it’s dynamic peak, however the short sustain time will mean that the sound will be cut off almost instantly. This is what will create the pluck sound in the synth. Set the decay time to around 200-700 milliseconds, this time depends on how long you want the pluck to last for. The decay will control how long it takes for the pluck to fade out into silence. You can then finally set the release to 0, this is because it will have no effect on the sound. This is because the sustain is set to 0, and the release can only go as high as the sustain goes in order for it to have audible effect.
Reverb and Delay
Reverb and delay can come very handy when you are trying to fill a mix, and here is where you will learn how. Delay is an effect that duplicates a sound and makes it echo over time, there are effects you can apply to the delay to make it sound more interesting over time. The delay repeating it’s self can fill in the mix of your music as the sound echo’s through the mix. Delay can also be used to create a trippy or dreamlike sound, this is why delay is very commonly used in the trance music genre. Reverb is an effect that is used to create a sense of space in your music. Reverb can be described as the acoustics of the sound that was previously produced, the reverb sustains the end of the sound that was played. Reverb can help give your music a sound of depth if you want it to. You can also add tail to your reverb which controls the decay of the reverb it’s self. Some reverb modules allow the decay to be insanely high, this can produce ambient and emotional sounds.
Reading List
Basic Wavez. 2021. Fundamentals of Audio Synthesis – Sound Design For Beginners. [online] Available at: <https://basicwavez.com/fundamentals-of-audio-synthesis/> [Accessed 3 May 2021].
Berklee Online, 2018. Synthesizer Basics: Amplitude, Oscillators, Timbre | Music Production | Berklee Online. Available at: <https://www.youtube.com/watch?v=c3udLCvoCC0> [Accessed 23 March 2021].
Medium. 2019. Basics of Synthesis and Sound Design — A Beginner’s Guide. [online] Available at: <https://medium.com/@kusekiakorame/basics-of-synthesis-and-sound-design-a-beginners-guide-9c3d0314c6d5> [Accessed 3 May 2021].